This invention relates to a positioning apparatus and more particularly to a locking hinge device for adjusting the degree of the tilt of the liquid crystal display (LCD) screen of a word processor.
In using word processors, it becomes more essential to make such devices more convenient and comfortable for an operator to use. For this purpose, an operator has to be able to alter the viewing angle of the screen surface to obtain the desired angle of tilt on the screen.
Normally, the prior art word processor has a tilt mechanism wherein a liquid crystal display (LCD) screen support hinge member is hinged to a hinge support base by means of torsion springs. The LCD screen support hinge member is tilted to adjust the viewing angle and held in the desired tilt position by the frictional force of the torsion springs.
This type of arrangement has been found to require complex construction. Also, in the proper functioning of the tilt mechanism, it is essential that the elasticity of the torsion springs has a suitable degree, i.e. neither too little, as the positioning of the screen then may be changed inadvertently, nor too large, as the positioning gets stiff and difficult.
Furthermore, the elasticity of the torsion spring will be lowered over a long term of use, thus preventing the tilt screen from being positioned in the desired tilt position with maximum stability.
Accordingly, it is an object of the present invention to provide a locking hinge device which is of simple construction.
It is another object of the present invention to provide a locking hinge device which enables the screen to be retained in the desired tilt position with maximum stability over a long period of use.